Static class always contains static members. Non-static class may contain both static and non-static methods. Static class does not contain an instance constructor.
Non-static class contains an instance constructor. Static class cannot inherit from another class. Non-static class can be inherited from another class. Skip to content. Change Language. Related Articles. Table of Contents. For example, if you have a static class that is named UtilityClass that has a public static method named MethodA , you call the method as shown in the following example:.
A static class can be used as a convenient container for sets of methods that just operate on input parameters and do not have to get or set any internal instance fields. For example, in the. Math class contains methods that perform mathematical operations, without any requirement to store or retrieve data that is unique to a particular instance of the Math class.
That is, you apply the members of the class by specifying the class name and the method name, as shown in the following example. As is the case with all class types, the type information for a static class is loaded by the. NET runtime when the program that references the class is loaded. The program cannot specify exactly when the class is loaded. However, it is guaranteed to be loaded and to have its fields initialized and its static constructor called before the class is referenced for the first time in your program.
A static constructor is only called one time, and a static class remains in memory for the lifetime of the application domain in which your program resides. To create a non-static class that allows only one instance of itself to be created, see Implementing Singleton in C.
Cannot contain Instance Constructors. Creating a static class is therefore basically the same as creating a class that contains only static members and a private constructor. A private constructor prevents the class from being instantiated. The advantage of using a static class is that the compiler can check to make sure that no instance members are accidentally added.
Add a comment. Active Oldest Votes. Here are some reasons why you might want to make them non-static: If they have or might eventually have some internal state. Cached login credentials, or cached lists of the top 10 tracks.
Stateful static classes are a bad idea! They are basically a poor implementation of a singleton. If you're going to have a lot of music sources, you may well want to perform some actions on all of them. Find a particular track from any source. With static classes you're going to need a line for each class. If you've got non-static classes you can just loop over a collection of them.
Improve this answer. Community Bot 1. By "design decision" I was referring to the decision by Mads Torgersen. There's nothing todo whith his decisions. NET does not support static inheritance You say: I want to get rid of all my redundant code and make it easier to create new music sources. Here again, inheritance is central Why did you initially make them static anyway? Matt Haynie 3 2 2 bronze badges. Frederik P. The reason why I made it static was because I want to access the class from anywhere and everywhere without having to pass around the object to every constructor.
Also, I only had a single source from the beginning so that's why inheritance was not obvious for me at the time I created the first class. Thats why thinking about what u might need in the future is a good thing. You say: "The reason why I made it static was because I want to access the class from anywhere and everywhere without having to pass around the object to every constructor" That is such a bad habit.
KonradMorawski It's impossible to write extension methods for static classes. You misunderstood me here. What I meant is that the functionality required in the scenario described by user could be provided in future by as little as allowing extension methods for static classes.
No static inheritance necessary. That's why his scenario didn't strike me as a very good rationale for introducing static inheritance. If C was to be modified in this aspect, why go for a major redesign when a minor one would be just as good in practice.
Learner That's not really fair. Net everything inherits from object , and everyone is expected to know that. So static classes always inherit from object , whether you specify it explicitly or not. Show 4 more comments. Andrew Hare Andrew Hare k 68 68 gold badges silver badges bronze badges. He wants to know why this was done. Why is it sealed? This doesn't answer the question it all; it just restates the issue he was asking about. Well, the OP should have asked "Why are static classes sealed", not "Why can't I inherit from static classes?
This answer gets my vote. AlexBudovski: This answer is correct but as useless as a telling a lost person "you are in front of me" when they ask you "where am I".
Think about it this way: you access static members via type name, like this: MyStaticType. MyStaticMember ; Thus, the new item bears no relationships to the original when used in code. So, in the end you don't really gain anything from inheriting static classes. Joel Coehoorn Joel Coehoorn k gold badges silver badges bronze badges. You cannot add methods to an existing static type via an extension method.
Please see my comment on the accepted answer for an example desired use. MyStaticType — user It would probably even be possible to define a convention via which languages could do so in a fashion compatible with the current CLR e.
I found myself with a case where I believe inheriting a static class is the right thing to do, although obviously you can access them anyway. I have a static class for sending raw data streams to the printer for talking to industrial label printers.
It has a bunch of windows API declarations. I now find myself writing another class for messing with printers which needs the same API calls. Not good. Declare them twice? Good, but not permitted. Amit Amit 1 1 gold badge 6 6 silver badges 11 11 bronze badges. I have a generic loader that receives a class as type. That class has 5 helper methods and 2 methods that return a string name and description. I might have picked it wrong I think so , but the only solution I found was to instantiate the class in the generic loader, to access the methods The alternative would be a giant dictionary, I guess.
Also, when you say "what you want to achieve" you should instead say "what you seem to be aiming for" or something similar. Yogesh Karekar Yogesh Karekar 31 1 1 bronze badge. That's what is left to me. I do it this way. And I don't like it. I've done it this way as well, but for some reason it doesn't feel aesthetic when you know you will never instantiate the object. I always agonize about details like this, despite the fact that there is no material cost of it.
Lucas Lucas Add 3. FocusedWolf FocusedWolf 13 13 silver badges 18 18 bronze badges. You can do something that will look like static inheritance. Kindle Q 2 2 gold badges 16 16 silver badges 27 27 bronze badges. Konard Konard 1, 17 17 silver badges 18 18 bronze badges.
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